Kubota B1830, Workshop Manual

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ENGINE B1830,B2230,B2530,B3030, WSM
1-S55
Free Length and Tilt of Valve Spring
1. Measure the free length (B) of valve spring with vernier calipers.
If the measurement is less than the allowable limit, replace it.
2. Put the valve spring on a surface plate, place a square on the
side of the valve spring.
3. Check to see if the entire side is in contact with the square.
Rotate the valve spring and measure the maximum tilt (A) .
If the measurement exceeds the allowable limit, replace it.
4. Check the entire surface of the valve spring for scratches.If
there is any defect, replace it.
9Y1210003ENS0084US0
Valve Spring Setting Load
1. Place the valve spring on a tester and compress it to the same
length it is actually compressed in the engine.
2. Read the compression load on the gauge.
3. If the measurement is less than the allowable limit, replace it.
9Y1210003ENS0085US0
Oil Clearance between Rocker Arm and Rocker Arm Shaft
1. Measure the rocker arm shaft O.D. with an outside micrometer.
2. Measure the rocker arm I.D. with an inside micrometer, and
then calculate the oil clearance.
3. If the oil clearance exceeds the allowable limit, replace the
rocker arm and measure the oil clearance again. If it still
exceeds the allowable limit, replace also the rocker arm shaft.
9Y1210003ENS0086US0
Tilt (A) Allowable limit
1.0 mm
0.039 in.
Free length (B)
Factory specification
37.0 to 37.5 mm
1.457 to 1.476 in.
Allowable limit
36.5 mm
1.437 in.
(A) Tilt (B) Free Length
Setting load /
Setting length
Factory specification
117.4 N / 31.0 mm
11.97 kgf / 31.0 mm
26.4 lbf / 1.22 in.
Allowable limit
100.0 N / 31.0 mm
10.2 kgf / 31.0 mm
22.5 lbf / 1.22 in.
Oil clearance between
rocker arm and rocker
arm shaft
Factory specification
0.016 to 0.045 mm
0.00063 to 0.00177 in.
Allowable limit
0.10 mm
0.0039 in.
Rocker arm shaft O.D. Factory specification
11.973 to 11.984 mm
0.4714 to 0.4718 in.
Rocker arm I.D. Factory specification
12.000 to 12.018 mm
0.4724 to 0.4731 in.
KiSC issued 05, 2012 A